A fire extinguishing system for a casing, preferably an electronics casing, consisting of an extinguishing agent container, in which the extinguishing agent is stored, and a control device for the flow of extinguishing agent is provided, wherein a preferably cuboid extinguishing agent container (2) forms together with the devices (5, 7, 8, 29, 31, 32) required for storing and monitoring the loss of extinguishing agent, for controlling the flow of extinguishing agent from the container and for connecting a discharge device for the extinguishing agent, a complex structural component (24, 28), and wherein the devices (5, 7, 8, 29, 31, 32) are fastened at or integrated in the extinguishing agent container (2) in such a manner that this may be transported, installed or arranged in the casing (18) as a compact structural component (FIG. 2).The invention has the advantage that all devices required for the extinguishing of fire, like extinguishing agent container, power supply unit, evaluation electronics, are able to be inserted with low space requirement in a quick and reliable manner into a casing according to the sense of the present document.